The present invention relates generally to a system and method for pumping a production fluid from a subterranean well, and particularly to an electric submergible pumping system having a shroud formed from a sheet material.
Pumping systems, such as electric submergible pumping systems are utilized in pumping oil and/or other production fluids from producing wells. A typical submergible pumping system includes components, such as a motor, motor protector, submergible pump and pump intake. In certain applications, a shroud is disposed about certain of the submergible components. For example, a shroud may be employed around the submergible motor to extend upwardly to the pump intake, where it is fastened to the submergible pumping system. Thus, the production fluid is drawn through the shroud, past the motor and into the pump intake. The produced fluid acts as a coolant when drawn past the submerged electric motor.
Conventional shrouds are formed from tubing having an inside diameter larger than the outside diameter of the submergible pumping system components. However, when the annular space between the well casing and the motor is relatively small, much of that space is taken by the wall thickness of the shroud tubing. In fact, in some situations the diameter of the tubing must be reduced to a point that the annular flow space becomes too small to provide sufficient fluid to the pump. This can starve the pump and ultimately damage the pump components. The narrow flow passage is also susceptible to clogging due to deposits or debris in the production fluid.
It would be advantageous to be able to utilize a downhole shroud in a narrow bore wellbore without undue utilization of the cross-sectional wellbore space potentially available as a fluid flow passage.
The present invention features a device for directing a production fluid along a motor used in a submergible pumping system deployable in a wellbore. The device includes a motor shroud sized to fit within a wellbore. The motor shroud includes a wall that defines an inner flow path of sufficient size to receive the motor therein. The wall of the motor shroud is corrugated to form a plurality of downflow and upflow passages, and a channel for the electrical power cable.
According to another aspect of the present invention, a submergible pumping system is provided for use in pumping a production fluid from a subterranean well. The system includes a submergible pump having a pump intake. Additionally, the system includes a submergible motor operably coupled to the submergible pump. A motor shroud is disposed over at least the submergible motor and the pump intake. The motor shroud is formed by a wall of sheet material. Typically, the sheet material is a sheet metal formed as a corrugated sheet.
According to another aspect of the invention, a method is provided for cooling a downhole component of a submergible pumping system disposed in a narrow wellbore. The method includes placing a corrugated sheet material around the downhole component to form an interior flow path between the sheet material and the downhole component. Additionally, an exterior flow path is formed between the sheet material and the narrow wellbore. The method further includes drawing a wellbore fluid through the exterior flow path in a first direction. Also, the method includes drawing the wellbore fluid through the interior flow path in a second direction.
According to another aspect of the present invention, a method is provided for assembling and deploying a submergible pumping system in a wellbore. The submergible pumping system has a plurality of submergible components and a shroud disposed about at least one of the submergible components. The shroud includes a deformable sidewall and an upper attachment end by which the shroud is coupled to at least one of the submergible components. The method includes assembling the shroud and those submergible components that are at least partially contained within the shroud. The method further includes mounting a first clamp about the shroud and a second clamp about at least one of the submergible components above the deformable sidewall. The method further includes supporting the clamps proximate an upper opening of the wellbore. Additionally, the method includes assembling the remainder of the submergible pumping system above the clamps.